conclusively established, and its delicacy having been shown to be far greater than that of the separation of alcohol by distillation, our authors availed themselves of this new process to carry out a fresh inquiry into the mode in which alcohol is disposed of when introduced into the stomach of a living animal.

Modern chemistry makes great use, in quantitative analysis, of what is termed the "method of volumes." Formerly, when a reagent was employed to throw down from its solution some substance whose amount had been determined, it was the precipitate that was carefully collected and weighed, no account being taken of the quantity of the reagent that was required for its production. But it is now found to be far more easy, and (with due precaution) not less accurate, to employ a test-liquid of a certain known strength, and to estimate the amount of the substance which it is employed to detect, by the quantity of it that may be required for the complete precipitation of that substance. This method, with a difference arising out of the nature of the case, was found applicable in the use of the chromic test for alcohol. A solution of bichromate of potass in sulphuric acid was prepared of a certain known strength, and a definite measure of it was put into a glass tube of fixed diameter. When air containing alcoholic vapour was passed through this, conversion of its red hue to emeraldgreen afforded a definite standard of comparison; and one tube being substituted after another, as the conversion became complete in each, until no further change could be perceived, the proportional amount of alcohol-vapour given off in different experiments was readily determinable by the total quantity of the solution thus changed; whilst the time required for the conversion, the quantity of air passed through the tube being the same, gave the measure of the proportion of alcohol vapour existing in the aira measure which was exceedingly ready and useful in the application of this process to the detection of alcohol in the products of respiration. Thus, in one of the experiments, a man having taken at breakfast a litre of red wine containing 10 per cent. of alcohol, and his meal having terminated at 10 A.M., his breath was found at noon and at 1 P.M. to convert a centimètre of the test-liquid in two minutes; at 2 P.M., in four minutes; at 4 P.M., in ten minutes; and at 5 P.M., in fifteen minutes; whilst at 6 P.M., after fifteen minutes the colour was but partially changed, and at 7 P.M. no conversion whatever took place; the gradual diminution, and the period of the entire cessation, of the elimination of alcohol by pulmonary exhalation being thus very definitely indicated. So, again, the urine of the same subject being submitted to the chromic-test at similar intervals, it was found that whilst 60 grammes of that excretion passed at mid-day gave of alcoholic vapour enough to change the colour of sixteen cubic centimètres

of the test-liquor; the same quantity passed at 2 P.M. produced the like effect on fifteen cubic centimètres; at 4 P.M., on twelve; at 6 P.M., on ten; at 8 P.M., on four; at 10 P.M., on one; whilst that passed at midnight gave but a very faint trace of the characteristic reaction.

It is not only, however, by the lungs and by the kidneys that the progressive elimination of alcohol is thus shown to be effected; for the application of the same method of research has enabled our authors to detect the presence of alcohol in the vapour exhaled from the skin of a dog in a state of alcoholic intoxication. And they have further been able to trace the passage of alcohol circulating in the blood-current into all the tissues of the body,-the liver and the brain, however, being the parts in which it most tends to accumulate. It is not a little curious that the proportions obtainable from these two organs should differ notably, according as the alcohol has been taken into the stomach and absorbed through the portal system (which will bring it into direct relation with the substance of the liver) into the general circulation, or as it has been at once introduced into the general circulation by direct injection. In the former case, the proportion of alcohol obtainable from a given weight of blood being represented by 1.00, the proportions yielded by the same weights of brain and liver were 134 and 1.48 respectively. But in the latter, the proportion obtainable from a given weight of blood being still represented by 100, the proportions yielded by the same weights of brain and liver were 3'00 and 1.75 respectively. In either case, the proportion obtainable from muscular flesh was much less than that yielded by the blood.

Experiments of this kind, repeated and varied in divers modes, seem to leave no doubt whatever, that not only is alcohol separated from the blood by the tissues of the body, especially the substance of the brain and of the liver, but that the excretory organs are continually engaged in its elimination, even when the quantity introduced into the system has been but small; and that the larger the quantity of alcohol introduced into the system, the longer is the period required for its entire removal from the circulating current. From these experiments our authors think themselves justified in drawing the conclusion, that alcohol undergoes no combustive action in the living body, but that the whole of what is ingested is excreted unchanged; so that this substance has no claim whatever to rank among articles of food, but must be placed in the category of those medicinal or toxic agents, whose presence in the living body exerts an important influence on its functions, though they do not themselves enter into combination with any of its components. They readily admit that they have not succeeded in reproducing in any instance from the excre

tory products the whole amount of the alcohol introduced into the system; but they very justly urge that such a demonstration cannot fairly be exacted, all circumstances considered; and that all the evidence which the nature of the case admits, points in one direction. For there is on the one hand, an entire absence of positive evidence that alcohol is eliminated from the system by a combustive process; whilst the assumption that it is so eliminated is opposed to the fact that none of the derivatives of alcohol are detectable in the blood, although the presence of either of them would be recognised without difficulty if it were really there; and is rendered still more improbable by the length of time during which alcohol can be shown to remain in the body, even when ingested in small quantities. On the other hand we have the positive evidence afforded by the detection of alcohol in the pulmonary and cutaneous exhalations and in the urinary excretion, in quantities at first considerable, but gradually diminishing with the increase of the interval, until (as parallel analyses of the blood and of the tissues indicate) there is reason to believe that this substance has been entirely removed from the system. Our authors justly lay stress on the fact that it is not the mere excess of alcohol, which the system cannot profitably use up, that finds its way into the excretions; for they detected alcohol in the urine of a man within half an hour after he had taken no more than 30 grammes (463 grains) of brandy; and in the case already cited, the ingestion of only a litre (or ordinary bottle) of weak wine gave rise to a continued elimination of alcohol by the lungs during eight hours, and by the kidneys during fourteen hours. A very striking proof of the length of time during which alcohol remains unmodified in the system, after being ingested in any considerable amount, is afforded by the fact that it was found in abundance in the brain, liver, and blood of a vigorous man, who died of the remote results of alcoholic poisoning thirty-two hours after drinking a litre of brandy, notwithstanding the early use of emetics and other remedial means.

If, then, we refrain from adopting our authors' conclusion as a demonstrated fact, we feel justified in admitting its claim (until any opposing data shall have been furnished by fresh inquiries) to as firm a basis of probability as that on which has been erected the greater part of the existing fabric of physiological doctrine. Doubtless the advocates of the "food" hypothesis will be both able and ready to show the insufficiency of the proofs on the strength of which that hypothesis is now pronounced to be fallacious: the candid inquirer, however, will not test the validity of the new doctrine by its accordance with one to which he has been long accustomed to give an unquestioning assent, but will rather turn his thoughts to the claims which the latter has upon his

acceptance, and will examine if these are really such as to demand his negation of the strong probabilities that can be urged on the other side. A very good rule in all such cases is to make the old and the new doctrine change places, admitting the new one, pro tempore, to the place which the old one has long held, and then considering whether, if the old one were now advanced for the first time, it would be able to establish any claim to reception. To us it appears perfectly clear that if the minds of physiologists had been in the first instance thoroughly imbued with the important facts adduced by the authors of the work before us, as to the progressive elimination of alcohol in substance from the living body by each of the three principal emunctories provided for the purification of the blood, they would have at once rejected as a baseless assumption the notion that alcohol undergoes a process of combustion in the body and is entitled to take rank as an alimentary material. If this be really so, this is surely the attitude which, on a fair balance of the evidence now before them, they are bound to assume in regard to this important question.

It is not requisite for us to follow our authors through their detailed inquiry into the pathology of alcoholic poisoning, since they do not add anything of importance to what was previously known on the subject, and their general result is in accordance with what has been commonly taught by physiologists and toxicologists in this country-namely, that alcohol in large doses exerts a specific influence, analogous to that of other narcotic poisons, upon the nervous centres; and that death results from the suspension of the respiratory movements, the heart continuing to beat for some time after these have ceased. The most important new fact which they have substantiated, is that of the presence of globules of fat distinguishable by the naked eye as brilliant points, floating on the surface of the blood drawn from animals in a state of alcoholic intoxication. That such a change should be produced by the ingestion of a single dose of alcohol is not a little remarkable, and fully confirms the statements of those pathologists who assert that the habitual excessive use of alcoholic drinks produces such a notable increase in the fatty matter of the blood, as altogether to pervert the constitution of the nutritive fluid. We may here mention that the same effect is produced on the blood by the anaesthetic agents, chloroform, sulphuric ether, and amylene; and it disappears, as do the other phenomena of intoxication, when (as is shown by chemical tests) the blood has been freed by the excretory processes from the presence of the toxic agent.

The second part of this valuable treatise is devoted to a similar inquiry into the modus operandi of anesthetic agents; chloroform, sulphuric ether, and amylene being specially investigated. As in the

case of alcohol, the first object was to devise an exact method of recognising the presence and estimating the amount of these substances in the vapours raised from the blood, the tissues, or the excretions of animals which had been subjected to their influence. In the case of chloroform (which is a compound of chlorine, hydrogen and carbon) advantage was taken of the change which its vapour undergoes when passed through a red-hot porcelain tube in contact with common air; the products of its decomposition being hydrochloric acid (the quantity of which is readily estimated by causing its vapour to pass through a solution of nitrate of silver, the amount of the precipitate of chloride of silver thus produced affording the measure of the amount of chloroform which had been subjected to the process), chloride of carbon which is deposited in crystals, and carbonic acid and chlorine which are set free. It was ascertained that no effect was produced upon the testing apparatus, when vaporized air was transmitted through it from the blood and tissues of animals to which chloroform had not been given, whilst the addition of a minute quantity of chloroform to these substances immediately gave the anticipated results; and when the blood and tissues of animals killed by the inhalation of chloroform were subjected to the same process, very decided evidence was obtained that it had been received into the circulation, and diffused through the body. Its special affinity for the substance of the brain was found to be even more remarkable than that of alcohol; the proportional amounts yielded by equivalent quantities of blood and of cerebral tissue being 100 and 3'92 parts respectively, whilst the liver yielded 2:08 parts, and the muscular substance generally 0 16 parts. The brain and liver, moreover, seemed to hold it more tenaciously than the blood; as it could be detected in those organs after it had disappeared from the blood. In the case of animals rendered temporarily insensible by the inhalation of chloroform, it was ascertained by the comparative examination of blood drawn during the state of insensibility, and of blood drawn when consciousness and motor power had returned, that the recovery from that state is coincident with the complete removal of chloroform from the blood. This removal is chiefly effected by the exhalation of its vapour from the lungs; the presence of chloroform being distinctly discoverable by the means already indicated in the breath of animals that are under its influence, but ceasing to be thus traceable at a much earlier period than the vapour of alcohol, as might be anticipated from the much more speedy supervention of recovery after the inhalation of chloroform than after alcoholic intoxication. Traces of chloroform are to be found also in the products of the cutaneous exhalation; but this substance has not been detected in the urine.